Composite technology provides the means for combining different materials together such as metals, plastics, ceramics, and the like to form multi-layered structures that provide different properties than a unitary material. Typically, these improved properties of composites concern mass, strength, wear resistance, heat resistance, electrical properties, magnetic properties, optical properties, and/or power densities along with many other properties. Humans have been using composites for many millennia including the formulations for brick using straw and mud and formulations for concrete using stones and cement. A current popular composite is fiberglass comprising glass fiber and polymer.
High end engineering composites include MMC (Metal Matrix Composites), PMC (Polymer Matrix Composites) and CMC (Ceramic Matrix Composites). Each of these composite systems are used for specific applications where unitary materials typically do not provide adequate material performance for the usage application. In many cases, fibers are used as reinforcement structures to help with the fracture toughness of the composite. These fibers could be polymer fibers, carbon fibers, ceramic fibers or glass fibers. In the case of CMC (Ceramic Matrix Composites), typically the key performance required is heat resistance. Most CMC are used at temperatures above 1000° C. while PMC (Polymer Matrix Composites) are typically limited to applications below 300° C. MMC (Metal Matrix Composites) are typically used for wear resistance and applications requiring stringent fracture toughness requirements.
CMC (Ceramic Matrix Composites) require very expensive/high energy usage processes. Also, CMCs can have manufacturing intervals lasting months. Typically, CMCs are made using carbon fibers or other high performance fibers as the reinforcement structure. Then, the pores or matrix is infiltrated with a ceramic. Techniques for infiltration include chemical vapor deposition, melt infiltration, polymer injection and pyrolysis using polymer derived ceramics.
The ceramic used in these processes includes silicon carbide (SiC) as well as all the possible polymers with silicon and carbon or aluminum in the backbone of a polymer-derived-ceramics. Specific property advantages of CMCs include high temperature operation, lighter weight structures, and better fracture toughness. Applications for CMCs include high end transportation applications in the automotive, airline, and aerospace industries.
The processes that make CMCs are time consuming, expensive, and energy inefficient. Other disadvantages of CMCs are the inability to use low-melting point materials with the ceramic matrix due to the high temperature processes associated with melt infiltration, chemical vapor deposition, and polymer injection pyrolysis (PIP). Usually infiltration materials had to be stable at temperatures above 1000° C. which would preclude the use of many organic, glass and low-melting point materials. The PIP process uses several cycles of the polymer-injection-pyrolysis to fill in the matrix due to the PDC shrinkage and the need to fill in void spaces. These temperatures typically exceed 1000° C. and can approach 1600° C. in certain cases. These temperatures will melt plastics and other low melting point metals such as aluminum and rule them out as being a material in the composite. What is clearly needed is cheaper and faster ways of making CMCs at lower temperatures. The lower temperature regime will allow for the existence of novel composite materials and structures which currently are not available.
Therefore, there is a need for ceramic composite structures using hundreds of conceivable compositions and combinations of materials to meet the industrial demand for materials that are light-weight, have low manufacturing costs, that can be tailored to perform in a myriad of applications, including, but not limited to, automotive, airline, aerospace, pharmaceutical, biotechnology, electronics, consumer packaged goods, oil, gas and geosciences.